Telephone



Jan. 16, 1923.

H. D. CONWAY.

TELEPHONE REPEATER SYSTEM.

2 SHEETS-SHEET l.

FILED DEC. ZY, 1918.

/Hl/eH/O/f: Roy@ Con Way l v f/"y,

Il .n.tll'lulil.

Jan. 16, 1928, 1,442,425.

y R. D. CONWAY. TELEPHONE REPEATER SYSTEM.

FILED DEC. 27,191.8. ZISHLETS-SHEET 2.

Patented Jan. 16, 1923.

lUNITED sTaTss PATENT OFFICE.

ROY D. CONWAY, OFy CHA'IHAM, NEW' JERSEY, ASSIGNOR T0 WESTERN ELECTRICCOMPANY, INCORPORATED, OF'NEW' YORK, N. Y., A CORPORATION 0F NEW YORK.

TELEPHONE `REP:E IIEIR. SYSTEIHI.

Application filed December 27, 1918. Serial No. 268,466.

p To all who/mI 'it may conce/izo:

Be it known that I, Roi' D. CoNwAr, a citizen of the United States,residimg` at Chatham, in the county of Morris, State or New Jersey, haveinvented certain new and useful improvements in Telephone RepeaterSystems, of which the following is a Jiull, clear, concise, and exactdescription. p

This invention relates to telephone repeater systems, and moreparticularly to such systems in which connectimf;` circuits for joining`telephone linesiare equipped with re.

peaters or amplifiers tor amplifying; talking currents.

ln systems oi this character the telephone .lines terminating at aparticular central office may be differently equipped for various kindsot service, and may vary in impedance. For example, some lines may formsides oi phantom circuits, and when so employed are equipped. with`phantomine,l apparatus; other lines may be equipped with compositeapparatus i'or permitting the simultaneous transmission of bothtelegraphic or sip-nah ing ond telephonie currents over the same line,and ystill other lines ma f be equipped with hoth phantoming andcomposite Aapparatus. lhen a repeater is associated with any telephoneline, it is usual to associate with the repeater an artificial balancingline or network (or several such networrs) whose. impedance simulatesthat of the telen phone line.

It is an object .of this invention to provide in such systems improvedmeans and methods for automatically selectingand associating balancingnetworks with `a re'- peater, when the repeater is connected with thetelephone line.

In systems of this character it is also usual to provide means fordisconnecting composite apparatus from the telephone line with which itis associated, and. it this disconnection takes place when a repeater isassociated with a telephone line, it is important that the compositehalancingz apparatus or network be disconnected at the same time. It istherefore another object of this invention to provide improved means forso automatically disconnecting the composite balancing' network wheneverthe composite apparatus is disconnected, whereby the telephone line withwhich the repeater is associated may be maintained in a balancedcondition.

In accordance with the various features of this invention, eachtelephone line is provided with selection-control apparatus operatingupon the connection of the central ofiice connecting circuit with aterminal oit the telephone line, and cooperating with selection-controlapparatus in the connecting` circuit to control the selection oi theproper balancing network or networks, and the as- Iin the connectingcircuit whereby the composite balancingnetwork is automatically andsimultaneously disconnected 'from the repeater.

For a more complete understanding of this invention, reference shouldbe" had to the following' description considered in connection with theaccompanying; drawings. which, with Fig. l arranged immediately aboveFig, 2, illustrate one embodiment ot this invention.

Referring to the drawings, there are shown telephone lines Nos. 1, 2,. 3and 4, lines Nos. 1 and 3 having different impedances and requiring'different types of balancing networks, line No. 2 being equipped withjsihantoniingr apparat-us 160, and line No. 4s being equipped with bothphantoming apparatus 128 and composite apparatus 124. A.. connecting);circuit A. equipped with two repeaters orlainpliners 100 and 200, one ofwhich simplifies telephone currents in one direction and the'other inthe opposite direc;

tion, is provided at the central oicel.

Potentiometers 101 and 201 are asso ciated with the input circuits ofthe amplitiers 100 and 200 'tor controlling the gain of the respectiveamplifiers, For controlling the adjustment oi these potentiometers thereare provided three potentiometer-control. re-

'for balancing the telephone line.

lays il, l5 and i6, controlled by the telephone lines with which theconnecting circuit is associated. Circuits of the potentiometer-controlrelays are controlled in such a manner that it one telephone 'linerequires a certain gain, and the other Line with which it is connectedby means ot the connecting circuit )l requires a greater gain, then oneor more ci' the three potentiometer'- control relays will be operated toadjust the potentiometers nto gire a gain which is approximately themean of that required by the two connected telephone lines whereby thetransmission etiiciency in one direct-ion is approximately equal to thatin the other -direction. The potentiometer adjusting relays 4d, lo andt6 are governed by intermediate control relays 21, 39, 40, lll, 4.12 and,62 connected with the leads B, C and D. Depending upon the gainrequired for a particular line., one of these leads or no lead isconnected with a contact ot the line selec-tion control relays ot thatline. Each of the leans after passing;` through the windings of theproper intermediate relays, is multipled to contacts ot Vthe cordselection control relays.

ln order that .the different telephone lines, with which the connectingcircuit may be associated, may be properly balanced, there are providedforassociation with each of the amplifiers various balancingnetworks in,accordance with the requirements of the different types of lines. For`association with the respective amplifiers there are provided phantombalancingnetworks 102 and 202, composite balancing` networks 103 and203, basic networks 104 and 105 (oiidizd'erent impedances) and 20%, 205(ciC different iinpedances), and building-out sections (networks) 106and 20G. A basic `network is one which is always employed in balancing`a telephone line regardless ot its impedance. There may be differenttypes of basic networks according to the value ot their impedance. Forexample,r a certain type oiE network may be employed in balancingylines, all having impedances up to a certain Value; another ltype may beemployed for balancing telephone lines having impedances falling withincertain redetermined limits. It the impedance of a line is greater thanthat oi the basic network, then a buildingout section, whose impedancecompensates for the difference, is employedy and both basic network .andthe building-out section are selected and connected with the repeaterFor convenience7 only a limited number otbalancin; networks are shown inthe drawings, but it should be understood that in practice a largernumber may be einployed,-the number, or course, being determined by thenumber of telephone lines terminating yat the central otice. i

The connection ot' these networks with the. repeaters is controlled byrelays whose selection is in turn controlled by a selection-controlrelay associated with each line (see relay '18 in line 1, relay 60 inline 2, relay 30 in line 3 and relay 6l in line ll) and cooper-- atingselection-control relays in the connect-- ing` circuits (see relays 1S)and 20 in one end and relays 31 and 32 in the other end). Theseselection-control relays control a set oit intermediate control relays21, 33, 39, 4:0, 4:1, and 62 for determining which (it any) oli thepotentiometer adjusting relays are to be operated.

ln order that the selectingl apparatus of only one cord circuit may beeffective at a time for selecting networks common to a plurality ot cordcircuits and telephone lines, there is provided in each cord circuit amaster relay l5. The circuit of each master relay is controlled by allother such relays, and when one is energized, the energizing circuits ofall other master relays are open. This is brought about by having' acommon battery lead extend in one direction through series contacts oliall master relays, and a common ground extend in the opposite directionthrough other' series contacts of the master relays.

l/Vith this short description of the system in mind7 this invention 'maybe clearly understood from a description or the operation of the systemdisclosed in the drawing. it will be assumed that line #l is to be con--nected with-'line rlhe central oiiice operator will therefore insertplug` 5 into ack l1 of line #1, and plug 6 into jack J3 oi line #3. Theconnection ol the plug 5 with the ack .l1 causes the operation ol'relays 7 and 8 over a circuit from battery through the right-hand normalcontact ot master relay lo, windings ot relays "l" and 9 in paral-` lel,sleeve contact ot' the plug' 5 and the 'jack J1, resista-nce 81 and thewinding oli relay 8 to ground. Relay 9 is nuirginal and does not operateat this time. vThe insertion of the plug 6 into the jack lg ot line #3causes the operation ot relay 10 over a circuit from battery throughresistance 32, windings of relays l0 and 1i in parallel, sleeve contactof the plug- 6 and the jack J3, resistancel 83 and the winding ot relay12 to ground.` llelays l1 and l2 are marginal and do not operate at thistime.

lt the apparatus ot no other cord circuit is selecting at this time7 themaster relay 15 ot cord circuit A will be operated over a circuit frombattery through the normal contacts of master relays in other cordcircuits, Contact 3l ot slow-operating'. switching relay 17, contact otrelay 10, contact ot relay 7, right-hand normal contact ot switchingrelay 16, winding of master relay 15 ot' cord circuit A. and contactsot' master relays in other cord circuits to ground; The

opening of the right-hand normal Contact of master relay 15 removes theshort circuit oli resistance 85, whereupon this resistance is includedin circuit with relays 7 8 and 9, and relay 8 releases, this relay beingmarginal and not holding up in series with the resistance 85 norenergizing in series with this resistance.

i Upon the operation ot the master relay 15 and the release ot marginalrelay 8, line selection control relay 18 associated with. line #loperates over a circuit from battery through the contacts oi othermaster relays, left-hand and middle alternate contacts olf master relay15 ot cord circuit il contact 88 ot switching relay 17, ring :5ontactsoli the plug -and jaclr J1, lower-normal contact of marginal relay 8 andthe winding oi line selection control relay 18 to ground. The operationot the master relay 15 also causes the operation of selection-controlrelays 19 and 29 associated with the cord circuit A, these relaysoperating over a circuit from battery through the right-hand alternatecontact oit master relay 15, `the right-hand normal Contact o19Aswitching relay 17, conductor 91 and the windings oi'I selection-controlrelays 19 and 2O in parallel to ground. rl'he operation oi"selection-control relays 18 and 19 causes the ope ation of relays 21 and22 over a-circuit troni battery through contacts of master relays ofother cord circuits, the lefthand alternate contact of master relay 15,conductor 92, winding olf relay 22, righthand contact of selectioncontrol relay 19, left-hand normal contact, winding and right-handnormal contact of relay 21, conductor D and the middle contact ofselection-control relay 18 to ground. Relay 21 in operating completes alocking circuit tor itself from battery over conductor 92, alternatecontact of relay 22, resistance an alternate contact winding and anotheralter-- nate contact of relay 21 to ground. The operation ofselection-control relays 18 and 29 causes the operation of relay 23vover a circuit from battery, over conductor 92, winding or' relay 22,conductor 97, lett-hand contact of relay 20, lower normal contactwinding and upper normal contact of relay 2.3, conductor 98, andleft-hand contact of selection-control relay 18 to ground, Relay 23 inoperating completes a locking circuit for itseltfrom battery overconductor 92, alternate contact of relay 22, resistance 211, conductor99, an alternate contact and winding and another alternate contact ofrelay 23 to ground. Relay 23, in closing its upper alternate contacts,connects the basic network 104 with conductors 134 and 135, and throughthese conductors and the normal contacts of relays 66, 136 and 72, withthe repeater 100 for balancing the line #1.

The locking up vof relays 21 and 23'opens the energizing circuit olrelay whereupon this relay releases its armature and establishes anoperating circuit tor relay 26, which now operates. Resistance 25 isconnected around the alternate contact of relay 22 to prevent therelease orn relays 21 and 23 while the arn'iature of relay is movingfrom its alternate to its normal contact. The operating` circuit torthis relay 26 may be traced from battery over conductor 92, normalContact o1 relay 22, windiiih it relay 26 and resistance 25 in parallel,insistance 2l and windings of relays 21 and 23 in parallel to ground.The operation of relay 26 causes the operation ot slow-operating relay17 over a circuit from battery, over conductor 92, contact of relay 26,conductor 90 and the winding olf relay 17 to grouniil.

rlhe operation of the switching relay 17 opens contact 84 in theenergizing circuit ot inaster relay 15, but before doing so, establishesan alternate holding circuit therefor from battery, through contact 86oit switching relay 17, contacts of relays 10 and 7, right-hand normalcontact of relay 16, winding or master relay 15 and contacts ofniasterrelays ot other cord circuits, to ground. The operation of switchingrelay 17 opens its right-hand normal contact in the energizing circuitof cord circuit selection-control relays 19 and 20, which thereuponrelease. Switching relay 17 in opening its contact 88, opens theenergizing circuit of line selection control relay 18, which thereuponreleases. The closure ot' contact 94- oi switching relay 17 causes theoperation of line selection control relay SO ot line .#8 over a eircuitfrom battery, through contact 911- ot switching relay 17, lett-handnormal contact of switching relay 16, ring contacts of the plug 6 andthe ack (L, lower normal contact ot marginal relay 12, and the windingoli line selection control relay 30 to ground. The closure oi: theright-hand alternate contact of switching relay 17 causes the operationof selection-control relays 81 and 32 over a circuit roni battery,through the right-hainl alternate contacts of master relay 15 andswitching relay 17, conductor 93, and the windings of relays 81 and 32in parallel to ground.

The operation of selection-control relays 30 and 81 causes the operationof relays 33 and 3l over a circuit from battery, over conductor 92,winding of relay 34, a contact ot selection-control relay 31,-conduetor80, a normal contact and winding and another normal contact of relay33,'conductor C, and the right-hand contact of selection-control relay30 to ground. Relay 38 in operating completes a locking circuit foritself from battery, over conductor 92, alternate contact of relay` 3l,resistance 146, an alternate contact and winding and another alternateof relay 35, and winding of relay 39 to ground. `lelay 39 in operatingcauses the operation ot potentiometer-control relay 45, which changesthe adjustment of both potentiometer-s.

rEhe operation of selection-control relays 30 and 32 before referred to,causes the operation ot relay 37 over a circuit trom battery, overconductor 92, winding ot relay 34, conductor 89, middle Contact otselectioncontrol relay 32, lower normal contact winding and upper normalcontact ot relay 37, conductor 95 and middle contact or" line selectioncontrol relay 30 to ground. Relay 37 in operating completes a lockingcircuit tor itself from battery, over conductor 92, alternate contact otrelay 34, resistance 146, an alternate contact and winding and anotheralternate cont-act oit relay 37 to ground. The operation of relay 37connects basic network 205 to conductors 156 and 157, and through theseconductors and the contacts of relays 49, 68 and 47 with repeater 200for balancing line #3. Upon the energization and locking-up ot relays 33and 37, relay 34 releases, thereby opening its alternate and closing itsnormal contacts. Resistance 147 'is connected around the alternatecontact of relay 34 to prevent the release ot relays and 37 while thearmature of relay 34 is moving from its alternate to its normal contact.Upon the closure ot the normal contact of relay 34, relay 38 operatesover a circuit from battery, over conductor 92, normal contact of relay34, winding of relay 38 and resistance 147 in parallel, resistance 146,the windings of relays 33 and 37 in parallel, and the winding of relay39 to ground. The operation of relay 38 causes the operation ofswitching relay 16 over a circuit from battery, over conduct-or 92,contact of relay 38, conductor 96 and the winding of switching relay 16to ground.

The operation ot switching relay 16, by opening its right-hand normalcontact, opens the circuit of master relay 15 and causes the releasethereof', but before this circuit is opened, a holding circuit for theother relays, which are held up over conductor 92, is established at theright-hand `alternate contact of switching relay 16. This holdingcircuit for these relays mty be traced from battery through contact 86of switching relay 17, contacts ot relays 10 and 7, righthand alternatecontact of switching relay 16, conductor 92, and windings of relays 21,23, 26, 33, 37, 38 and 39 to ground. The opening of the lett-hand normalContact ot switching relay 16 opens the energizing circuit of lineselection control relay 30, which thereupon releases its armatures. Theclosure ot the lett-hand alternate contact of switching relay 16establishes a short circuit for the resistance 82, thereby permittingthe operation of marginal relay 12 which disconnects the line selectioncontrol relay 30 from the ring talking strand, and connects the lineconductors of line #3 to the tip and ring contacts ot the jack ot thatline. The release of master relay 15 opens its righthand alternatecontact, thereby opening the energizing circuits of sel ect-ion controlrelays 31 and 32, which thereupon release their armatures. The closureot' the right-hand normal contact of master relay 15 establishes a shortcircuit 'for the resistance 85, whereupon marginal relay 8 ot line #1operates to disconnect the line selection control relay 18 from the ringtalking conductor, and to connect the line conductors ot line #1 to thetip and ring contacts of the ack of that line. Line #1 is now balancedby basic network 104 and line #3 by basic network 205, and thepotentiometers 101 and 201 are set so that the two upper sectionsthereof are effective. The 'two lines #1 and #3 being connected togetherby the cord circuit A, and its repeaters 100 and 200, are in conditionfor conversation between the stations joined thereby.

1t will be apparent that the selection o'l.t the networks and theadjustment ot the potentiometers to obtain the proper gain oi therepeaters, take place before the two lines are connected together,thereby avoiding disagreeable clicks over the lines.

If connection is to be established between line #2 and line #4, theplugs 5 and 6 ot the cord circuit A are inserted into jacks J 2 and J 4ot the respective lines. The connection of the plug 5 with the j ack J 2causes the operation of relays 7 and 56, while the insertion ot the plug6 into the jack J 4 causes the operation of relays 10 and 59. Theoperating circuit for relays 7 and 56 is from battery Vthrough theright-hand normal contact of master relay 15, the windings of relays 7and 9 in parallel, sleeve contacts ot the plug 5 and the ack J 2,resistance 73 and the winding of the marginal relay 56 to ground, andthat for relays 10 and 59 .is from battery, through resistance 82,windings of relays 10 and 11 in parallel, sleeve contacts of the plug 6and the jack J normal contact of relay 120, and windings ot relays 59and 57 to ground. Relay 57 is marginal and does not operate whenresistance 82 is in circuit therewith. Relay 11 is also marginal anddoes not operate when connected in circuit with relays 59 and 57. Theoperation ot relays 7 and 10, it the apparatus ot no other cord circuitis at this time selecting, causes the operation of master relay 15 inthe manner previously described. Relay 15 in opening its right-handnormal contact, removes the short circuit of the resistance 85, therebyincluding this resistance in circuit with relays 7, 9 and 56, whereuponmarginal relay 56 releases its armatures, closing an operating circuitfor line selection control relay 60.

master relay 15, right-hand alternate contact ot switching relay 17,conductor 93 and the windings of selection-control"relays 31 and 32 inparallel, to ground.

rlhe operation of line selection control relay 61 and selection-controlrelay 32 Causes the operation ot' relays 34 and 77 over a circuit frombattery supplied over conductor 92, through the Winding of relay 34,conductor 89, right-hand Contact of relay 32, lower normal contact,Winding and upper normal contactl of relay 77, conductor 78 and acontact of line selection control relay 61 to ground. Relay 77 inoperating completes a locking circuit for itselt from battery suppliedover conductor 92, through the alternate contact of relay 34, resistance146, an alternate contact winding and another alternate. contact or'relay 77 to ground. The closure of the uppermost contacts of relay 77connects the basic network 204 with the conductors 156 and 157. Theoperation of line selection control relay 61 and selection control relay32 also causes the operation of relay 36 over a circuit from batterysupplied over conductor 92,through the Winding of relay 34, conductor89, lefthand contact of relay 32, right-hand normal contact, winding andlett-hand normal contact of relay 36, conductor 79 and a contact ofrelay 61 to ground. Relay 36 in operating completes a locking circuitfor itself over a circuit from battery supplied over conductor 92,through the alternate contact of relay 34, resistance 146, righthandalternate contact, Winding and lefthand alternate contact ot relay 36 toground. The closure of a lett-hand alternate Contact of relay 36 causesthe operation of relays 49 and 50, the former opening up contacts inconductors 156 and 157 and the latter connecting the phantom-balancingset 202 with these conductors for balancing the phantom coil 123connected in thc line #4.

The operation of line selection control relay 61 and selection controlrelay 31 causes the operation of relays 35 and 67 to control theconnection of the composite balancing" set 203 and the building-outsection 206 with conductors 156 and 157 'for assisting in balancing theline #4. The operating circuit for relay 35 may be traced from batterysupplied over conductor 92, through the Winding of relay 34, a contactof relay 31, right-hand normal contact, Winding and left-hand normalContact of relay 35, conductor 29 and a contact of relay 61 to ground.Relay 35 immediately completes a locking circuit for itself from batterysupplied oVer conductor 92, through the alternate contact of relay 34,resistance 146, right-hand alternate Contact, winding and left-handalternate contact ot relay 35 to ground. The closure of a left-handalternate contact oit relay 35 causes the operation of relays 47 and 48,the former opening up conductors 156 and 157, and the latter connectingbuilding-out section 206 with these conductors. The operating circuitfor relay 67 may be traced from battery supplied over conductor 92,through the Winding of relay 34, a contact of relay 31, con'- ductor122, right-hand normal contact, Winding and left-hand normal contact ot'relay 67, conductor 28 and a contact' of relay 6l to ground. Relay 67,in operating, completes a locking circuit for itself Which may be tracedtrom battery supplied' over conductor 92 through the alternate contactof relay 34, resistance 146, right-hand alternate. Contact, Winding andlett-hand alternate contact or' relay 67 to ground. The closure of aleft-hand alternate contact ot' relay 67 causes the operation of relays68 and 69 over a circuit from battery through the contact oit relay 11,conductor 27, Windings oit relays 68 and 69 and a left-hand alternatecontact ot' relay 67 to ground. The operation of relay 68 opens up theconductors 156 and 157, and the operation ot relay 69 connects compositebalancing set 203 With these conductors. Relays 77, 36, 67 and 35 arenow locked up, whereupon the energizing circuit of relay 34 is opened.The resulting release of this relay 34 closes an operating circuit forrelay 38 which may be traced from battery supplied over conductor 92,through the normal Contact of relay 34, winding of relay 38 andresistance 147, resistance 146 and the windings of the four relays 35,36, 67 and 77 in parallelto ground.

Relay 38, in operating, causes the operation olf switching relay 16 overa circuit troni battery supplied over conductor 92, through the contactof relay 38, conductor 96 and the Winding of switching relay 16 toground. The closure ot the right-hand alternate contact ot relay 16supplies battery to conductor 92, through the contacts ot' switchingrelay 17 and relays 7 and 10, so that upon the opening ot the right-handnormal contact oi relay 16 and the resulting release ot relay 15, relays26, 35, 38, 63, 64, 67, 70 and 77 will be held up over conductor 92. `heopening of the lett-hand normal contact of relay 16 causes the releaseof line selection control relay 61, and the closure ot the lett-handalternate contact of this relay 16 establishes a short circuitI for theresistance 82, Whereupon marginal relay 57 olf line #,134 operates. Thisrelay 57 in operating opens its normal contact, disconnecting the lineselection control relay 61 from the line jt/:4; closes its upper andmiddle alternate contacts, connecting the line Wires of line .#-4 witht-he tip and ring contacts of ack J4; and closes its lower alternatecontact, causing the operation o't' marginal relay 120 over a circuitfrom battery through Contact 94 of switching relay 17, left-handalternate contact ot' switching relay 16, windings of relays 10 and 11in parallel, ,sleeve contacts oi the plug 6 and the jack J4, winding of`relay 120, left-, hand contact ot relay 58 and the lower alternatecontact of relay 5i' to ground. rlhe operation ot relay 120 closes itslower alternate contact before the normal conta-ct thereot' is opened,whereby relays 59 and 5E' are maintained energized whenA their originalenergizing circuit is opened. Master relay 15, in releasing upon theenergization ot the switching relay 16, closes its right-hand normalcontact, thereby establishing a short circuit tor the resistance 85,whereupon the marginal relay 56 is operated to disconnect line selectioncontrol relay 60 from the line and to extend line :ft2 with the tipI andring contacts ot' the jack J2. Lines 2 and are now connected 'jorconversation with basic network 105, building-out section 106 and thephantom balancing set 102 connected with the repeater 100 for balancingline :ft/:2, and the phantom coil 160 connected therewith and with basicnetwork 204, buildingoutsection 206, phantom balancing set 202 andcomposite balancing set 2033 connected with the repeater 200 toroalancingthe line :itiland the phantom coil 123 and composite 'set(apparatus) connected therewith.

The settings ot the potentiometers 101 and 201 are such that the twoupper sections thereof are effective for controlling the inputs ot' therespective nmpliers.

lit while lines 2 and e are connected for conversation, the compositeset 124 is disconnected from line #4, the organization of apparatus andcircuits is such that the composite balancing set 203 is immediately andautomatically removed trom the circuit. The disconnection or' thecomposite set is brought about by connecting a plug 125 in each ot thejacks 126 and 127, whereupon relays 128 and 129 operate over circuitfrom battery through the winding of relay 128, alternate contact oi"jack 127, alternate Contact ot jack 126 and the winding of relay 129 toground. ylhe operation ot these two relays disconnects the composite set1211 from line :fc/:4, and reestablishes the line through the alternatecontacts ot these relays. Re-A lay 128 also closes its lower alternatecontact, thereby including resistance 130 in parallel with the windingof relay 120, thereby reducing the resistance in circuit with thecontrol relay 11 whereupon this relay operates to open the energizingcircuits of relays 68 and 69. The release oit' relay 69 disconnects thecomposite balancing set 203 from the conductors 156 and 157, and therelease of relay 68 reestablishes the continuity of conductors 156 and157.

ln the earlier part oi the description 0i the system shown` in thedrawings, it has `been stated that lor convenience only a limnetwork, orrelays similar ited number ol.E basic networlrs, lmilding-out sections.composite balancing sets and phan tom balancing were shown, ano that inpractice the nuinlier ot these balancing arrangements would very likelybe greatly increased, depending, ot' course, upon the numher anddifferent types or lines entering the central oiiice. lt other balancingarrangements similar to those shown in the drawing are to be provided,then, ior each such balancing arrangement, t 1ere must be proyided arelay, similar to relay 23, i'or each basic to 70, T1 and 72 for eachbalancing-out seccion, composite balancing set and phantom balancingset. Each control relay similar to 23 and '70, so

provided, would oe controlled in the same manner, namely, from. acontact on a connecting circuit sclecti .i control relay similar to 19,and from contact on a line selection control relay similar to 18.

ln order that a complete understanding nia be had o1' the manner inwhich the potentiometer-control relays all, l5 and i6 adjust t-hepotent-ionieters 101 and 201 to secure a gain suitable 'for the lineswhich are connected together by means of the cord circuit lit, thefollowing brie-t description oi' the operation of the intermediatecontrol relays 21, 33, 89, 40, 41, 42 and 62 will be given. Theseintermediate control relays are, of course, under the control ot' thecord and line selection control relays.

lt two lines of the type represented by line .#1 are connected togetherloy means oi' the cord circuit A., then intermediate control relays 21and l0 operate and loclt up, causing the energisation otpotentiometer-control relay l over a circuit from battery through thewinding of this relay, extreme left-hand contact ot relay 410 andextreme right-hand contact of relay 21 to ground. The two upper sectionsof the potentiometers are therefore eectivc for controlling the gain ofthe repeaters. Upon the connection of the cord circuit' A with twolines, ot the type represented by line :#2, then intermediate controlrelays Ail, 62 and 39 are operated. Relay 39 causes the operation otpotentioineter-control relay l5, and the operation or. relays 62 and L11causes the operation of potentioineter-control relay i6 over a circuitfrom battery through the winding of this relay 16, extreme right-handcontct of relay 62, and extreme lett-hand contact ot relay Lil toground. lith potentiometer control relays 4to and i6 operated, thepotentionieteis are adjusted so that the three upper sections thereoilare effective tor controlling the gain of the repeaters. lf two lines ofthe type represented by line :lt/:3 are connected. together by means ofthe cord circuit A, then intermediate control relays 33, 39 and l2 areoperated, rel-ay 39 causing the operation of potentioineter-controlrelay 45,

and the operation ot relays and 42 causing the operation otpotentiometer control relay over a cir-cuit troni battery through thewinding o'j this relay 44 and the extrenie right-hand contacts of'relays anc to A relay is operated, all of the sections et thepotentiometer are effective tor controlling the gain oit' the repeaters.lt two lines ot the type represented by line are connected together,none of the intermediate control or potentionieter-control relays areoperated, 'fhereby the setting of the potentiometers remains n il withthe upper ol the four sections there-oi eilective 'tor controlling` thegain ot' the repeaters.

lt.' line irl it connected with line through the cooperation et the plug5 with line :liti and the plug G with line #2, then intermediate controlrelays 2l, 39 and 4l are operated, and ii by the cooperation or" theplug 6 with line #l and the plug 5 with line #2, intermediate controlrelays 42, 62 and are operated. ln either case, potentiometer controlrelay 45 is operated, renderiup,- the two upper sections of thepotentiometers effective for controlling the gain of the repeaters. Whenline #l is connected with line ,t3 through the cooperation of the plug 5With line #l and the plug;` G with line #3, intermediate control relaysl2i, 33 and 39 are operated, and when through the cooperation ot' theplug G with line and the plug 5 w'tli line itil, intermediate controlrelays 40, 42 and 39 operated. ln either case, potentionietcr-controlrelay 45 is operated. YWith line :itl-l connected with line through thecooperation ot the plu" 5 with line #l and the plug 6 With line :Itintermediate control relay 2l is operated, and it through thecooperation ot the plug;` 6 with line l and the plug 5 with line .#14,intermediate control relay 40 is operated. In either case. none of thepotentionieter-control relays are operated, whereby the setting of thepotentioineters is not altered.

Should line :At't2 be connected With line through the cooperation of theplug 5 with the former and the plug 6 `with the latter, intermediatecontrol relays 32. 33 and 39 are operated, causing,` the operation ofpotentiometer-control relays 45 and 46, and it through thecooperationoi2 the plug 6 with line and the plug 5 with line #8,intermediate control relays 4l, 42 and 39 are operated to cause theoperation ot the sarne potentionieter-control relays. By connecting`together lines :111:2 and Tt/'c4 through the cooperation ot the plug 5with the former and the plug 6 with the latter, intermediate controlrelays 62 and 39 are operated, which cause the operation ofpotentiometer control relay 45, While through the cooperation ot theplug 6 with line ,ft2 and the plug 5 with 1. iti Q line #4, intermediatecontrol relays 4l and round. lllhen potentiometer controly of thecombination, telephone line, an artii'icial balancing line,y a repeater.a connecting` circuit for associating ti. repeater with the telephoneline, a contr. relay normally associated rr'th the telephone line, acontrol relay assoc ed u'ith'the connecting circuit and cooperatino1with theline control relay upon the association o1e the connectingcircuit with the telephone line for controlling the connection of theartificial line 'with the repeater vtor balancing the telephone line,and means thereupon rendered ellfective for disconnecting the linecontrol relay from the telephone line.

2. ln a telephone repeater system, in coinination. a telephone line, anartilicial balancing` line, a repeater, a connecting circuit forassociating the repeater with the telephone line, a control relaynormally associated with the telephone line, a control relay associatedwith the connecting circuit and cooperating' with the line control relayupon the association et the connecting circuit With the telephone line.tor controlling the connection of the artificial line with the repeaterfor balancing the telephone line, and a relay thereupon renderedeffective for disconnecting the line control relay from the telephoneline.

3. ln a telephone repeater system, in conibination. a telephone line, anartificial bal an'cing line, a repeater, a connecting circuit forassociating the repeater with the telephone line, a control relaynormally asso` ciated with the telephone line and operating` over acircuit inc-hiding` a port-ion of the talking circuit of the associatedline and connecting circuit, a control relay associated with theconnecting` circuit and cooperating with the line control relay tocontrol the association of the artificial balancing line with therepeater for balancing the telephone line, and a relay operating afterthe association of the articial balancing line with the repeater tordisconnecting the line control relay troni the telephone line.

4. In a telephone repeater system, in cornbination, a telephone line, anartificial balancing line, a repeater, means rfor associating` f therepeater with the telephone line, a control relay normally associatedWith the telephone line, a control relay associated with the ronnectingmeans, a. relay operating when both control relaysareenergized toassociate the artilicial balancing line with the repeater' Vforbalancing the telephone line, and a relay thereafter `responsive it'ordisconnecting the linev control relay from the telephone line.

5. In a telephone repeater system, in combination, a plurality oftelephone lines, a plurality of artificial balancing lines,'a repeater,means for connecting vt-he repeater with one of thetelephone lines, aselectioncontrol relay vnormally connected with the engagedtelephoneline, a selection-control relay associated with the connecting means andcooperating with the line selection control relay toselect and connectwith the repeater one of the artificial balancing lines, and a relayrendered effective upon the connection of the artificial lineuwith therepeater for` disconnecting-,the line selection control relay from the`telephoner line.

6. In a telephone repeater system, in combination, a plurality oi'`telephone lines, a plurality of artificial balancingclines, a repeater,means for connecting the repeater with one of the telephone lines, aselectioncontrol relay operating over a .circuit including a portion ofthe talking circuit or" the telephone line and the connecting means,

a selection-control relay associated with the connecting means andcooperating with the operated line selection control relay to selectandiconnect with the repeater one of the 'artificial balancing lines,and means rendered effective upon the connection of the `arti ficialline with the repeater for disabling` the operating circuit of the lineselection ccntrol relay. V

Y 7. In a telephone repeater system, in combination, two telephonelines, a plurality of balancing lines, two repeaters for interconnectingsaid telephone lines, means for associating the repeatersl with theyrespective telephone lines, means for selecting and associating one ofthefbalancing lines with each repeater for balancing the respectiveassociated line, means responsive to the association of the repeaterswith the telephone li ues `for rendering the selecting means elfe@- tivclorselectingz' one balancing line. and "ns operative after suchselection for ren-A de. f the selecting mea-ns effective for selectinganothery balancing line.

8. In a telephone repeater system 7in combination. two telephone lines,a plurality of balancing lines, two repeaters for intercom necting saidtelephone lines, means forassociating the repeaters with the respectivetoleplione lines, means for 'selecting Yandasseciating a balancing linewith each repeater iior balancing the` respective associated lines, aswitching relay operating upon the asso-` ciation of the repeaters withboth lines for 9. ln a telephone repeater system, in combination, atelephone line, auxiliary apparatus associated therewith, a repeater, anartificial balancingl line `for balancing the telephone line, anauxiliary balancing set for balancing the auxiliary apparatus, meansYfor associating the artificial line and auxiliary set with therepeater'for balancing the telephone line and associated auxiliaryapparatus, ineans for disconnecting the auxiliaryV apparatus fromtlietelephone line, and marginal means responsive to4 such disconnectionto disconnect the auxiliary balancing set from the repeater.

l0. `In a telephone repeater system, )in combination, a telephone line,auxiliary apparatus associatedtherewith, a repeater, an artificialbalancing line for 'balancing the telephone line, an auxiliary balancingset for balancing the auxiliary apparatus, means for associating. theartificial line and auxiliary set with the repeater forfbalancing thetelephone vline and associated auxiliary apparatus, means fordisconnecting the auxiliary apparatus from the telephone line, a

marginalrelay operating upon-such disconnection, and means responsive to'the operation of the relay for disconnecting the auxiliary balancingset from the repeater.

il, ln a telephone repeater system, in combination, a telephone line,auxiliary appa.'atus associated therewith, a repeater, an artificialbalancing line 'for balancing the telephone line, an auxiliary balancingset for balancing the auxiliary apparatus, means for associating tbeartificial line and auxiliary set with the repeater f'or balancing thetelephone line and associated auxiliary apparatus, means fordisconnecting the auxiliary apparatus from thev telephone line, amarginal relay controlling the disconnection of the auxiliary balancingset from the repeater, and an operating circuit therefor whoseresistance is lowered by tbe disconnec tion of the auxiliary apparatusfrom the tele- `plume line, whereby the marginal relay is operatetb i `IZflu a telephone repeater system, in

combination. a plurality of telphone lines, a

repeater, a' plurality el.` balancing lines,

switching means `for associating one of the i other repeaters.` Whileathan repeater l.. liu; ai telephone repeater system', in conibinatioin aplurality et telephone lines, terminal apparatus for each t'elelfinoueline normally disconnected therefrom@,arepeater7 means ior connectingtherepeater withd the terminal: apparatus ot. one linenaf plurality ot'artiiicial balancing lines, switchingnieans ilor associating.; one otthe balancingy lines with thel repeater, and; means for subsequentlycoi'inecting the associated: balancing line, repeater and-terminaliapparatus Wit-h the telephone line whereby said: repeater; is maderesponsive toi currents in said;` lastmentioned teleplieneline.

14. In; a ,telephoneu repeaterr syste-in,. in conibinat'ioin twotelephone linesT a plurality ot balancing; linesa: connecting?l circuitfor associ atinifdi;l thef repeaterswith: the: telephone lines,automatic selecting: means: for selects ing; anch associating;balancing'. lines; with the respective repeaters for balancing the44refspectivefteleplione'lines, andinieansfo n thereafter connecting;tlietelephone f lines to gather through the connect-ingr circuit wherebyin-4 tercommuni'cation, between said; telephone linesmaybeestablished;

15; In: atelephone repeaterl systenn4 iiiy combination', twoitelephonellines; ,a pluralityA ot; balancing lines, two repeaters-.1, a.connecting; circuit foihassoeiating the-repeatersfwitlitbe-telephonelines, ai plurality otielay `rendered' effective upoin the:association oli the 11e peaters e with tlie tele-.phone linestoriseleet'- ing and associatingbii'lancingf lines witlu theV respectiverepeal'ers-/a anch relays operating. upon said'. selection andiassociation; for con necting;tlieftelephone lines together tliroiigh theconnecting circuiti.

16.'. linfa signaling.' systenn. ai plurality of lines oI different'.types,y repeaters ton` inter-- connecting said, lines; balancingrnetworks for said lines; andfa relayl individual toieachi repeater, saidrelay 'operating7 .Whentl'ieeorresponding: repeater.' is usedi for:Yconnecting.' lin es, to A.i'rstcause the.-select'fingfofy ainetiwoiilrsuitable fonbalamcing; the-line WithwhichA one'end ot thefrepeaterisassociated, and thereafter canseJ the selection oi" a' networleisuitable to balanceltbefline associatedwith'v the'rotlier end off the;Arepeater. .saidi relay al so" prever 'nig the selectioni ofi networl by'A sesV le'etingi;

17'.' ln signaling system a plurality"off lines ofi. di ferentn typ estrepeaters #fori inter connect gidulines, balanicingnetworls-fcrsaid.linessandairelay indiriidual to eaeh`re` p eaten sai d rel ayoperating, Whenithe corre spending: repeater is=y used? fon connectinglines` to rst cause; theeseleetion of ainetworle' suitable fonbalanoingthef line with which; once endf. off thee repeater'lisassociated,V andi thereafter' cause thee seleetioir ofi ai."network`vsuitable to balan'cethefline associated with? the other end of therepeater, the circuits of said relays for the several repeaters being;so arranged that Whenthe-rela-y ot one repeater energizedV during; theprocess of network selection., the circuits of the relays oic otherrepeaters will be held until the processof selection for that repeateris completed;

18. The method of selecting balancing lines for two signaltransmissionlines which areV to be interconnected through a repeater circuit, whichrcomprises associating, said repeater circuit with said lines Whilestill` pre1 venting; inteicoininunication between; said' linesselecting.the proper balancing line for one of saidll transmission linesselecting; the proper balancingline forthe other* of saidtransmissionlines after said first' selection ,is

completed?, andsubsequently'connecting said lines athroughi saidfrepeateroircuit for intercoininunicationf purposes:l p

19: In au repeater systemrtwo real linesna i plurality ol?arti'cialnetworhs:fon saiclreal lines, af repeater` circuitiV forYinterconnecting said;reallines;l means` for associating' sai d. re-

peatenz circuit withv said real' line'sgA andg switching; meansVresponsive to said associa-L tionz for; selecting: an artificialnetwork: for onev ot saidirealilines and subsequently'fselect-v ing'.aiiiartfiiieialinetworlc for the other oi2g saidy reahlines.

20: lfnia repeater: systeni,.t`wo reallines, aJ plurality o'fartificiali networks 1 lor saidy reallines,=. a. repeater circuitfor.interconnect-ing saiilreal lines, means for' associatiiig-v saidAifepeater'circuit with said ,real-lines, switel'iing means responsiveyto saidl association forv selecting an', artificial' network` for eachofsaid!y real: lines, andir ineanscoinprisingf relays for! (.ontiioll'in'g`I said l selecting 'meanstoc'a'iise` an artificial network for one ofsaid'I real line'sfto beselectedf only after' an artificial network@ hasbeen: si-zlected for theother ot saidf reali' l ines. y

2-1. 'n airepeater` system;` aI signal transmission line; auxiliaryapparatusv normally associatedE thereivit'liV an artificial linel forbalancing' saidi sig-nal transmission line, anVV auxiliary' balancing'set? 'for balancing saidauxiliary apparatiw switching means fordisconnect]ngfsaidf'auxiliary apparatus `from said! line and marginalmeans respons-iveto l balancing;

Yico

lil() ii'i'a'rginal means responsive to the operation of saidsiifiteliin'gnie'aznsfor' rendering' said balancing set-A inefectivez:

23. .The metho'cllot interconnecting a" signal transmission line, abalancing line there- :naa-spies for and a repeater, which comprisesconnectingg,` said balancing` line to said repeater and subsequentlyconnecting in response to said tirst connection said repeater andbalancing line to said telephone line to cause said repeater to beresponsive to currents in said transmission line.

The method of' establishing communication between two signaltransmission lines through a repeater circuit, which comprisesassociating with said repeater a balancing line tor each or' saidtransmission lines, and subsequently in response to said associationconnecting said repeater and said balancing lines to said transmissionlines whereby intercommunication therebetween may be established.

25. In a telephone repeater system, a plurality of telephone lines, arepeater, a plural ity of balancing lines, switching means forassociating one of said balancing lines with said repeater, and meanscomprising a relay responsive to the association ot said balancing linewith said repeater 'for subsequently connecting said repeater andbalancing line with a telephone line.

26. In a signaling system, a plurality of lines or different typesadapted to be inter connected by any one of a plurality of twowayrepeaters, and a master relay individual to each repeater, each ott saidrelays operating when the corresponding repeater is used 'For connectinglines to iirst cause the selecting of a network suitable for balancingthe line with which one end ot the repeater is associated, andthereafter cause the selection of a network suitable to balance the lineassociated with the other end of the repeater and means tor preventingthe simultaneous operation of two of said master relays, each of whichis normally adapted to select a common balancing network.

27. In a signaling system a plurality ot lines ol different types,repeaters ttor interconnecting said lines, balancing networks for saidlines, and switching means associated with each repeater and responsiveto the association of its repeater with two of said lines -for causing,iirst, the selection of a network suitable for balancing the line withwhich one end of the repeater is associated and thereafter causing theselection of anetwork suitable to balance the line associated with theother end of the repeater,

28, In a signalin system, a plurality of lines of different types.repeaters 'For interconnectingr said lines, balancing networks vFor saidlines, and a relay ii'ulividual to each repeater operative when thecorresiionding` repeater is used toi' interconnenting` lines to causethe selection ot balancing networks 'tor the lines, and to prevent theselection of nets works by other repeaters while that repeater isselecting, movable contacts for said relays, a source of current, saidrelays when deencrgized having movable contacts serially connected withsaid source and havino otheil movable contacts serially connectY 'l' teground.

In a signaling system, a plurality of lines ot different types,repeaters 'for interconnecting said lines, balancing networks for saidlines, and a relay individual to each repeater operative when thecorresponding repeater is used for interconnecting lines to cause theselection of balancing networks for the lines and to prevent theselection of networks by other repeaters while that repeater isselecting, movable contacts and electrical windings for said relays,each of said relays having a plurality ot movable contacts seriallyconnected with contacts of other of said relays when the electricalwindings of said relays are in the same electrical condition.

30. rIhe method of balancing` a plurality of signal transmission lineshaving different impedances in which a common basic net work and aplurality of building-out sections are employed, which method comprisesconnecting in circuit with one of said transmission lines which is to bebalanced, a basic network, disconnecting said network and subsequentlyconnecting in circuit with another transmission line which is to bebalanced said basic network and one ot' said building-out sections.

3l, In a signaling system, a plurality of real lines having); differentimpedances to be balanced, a basic network and a pluralitj,7 ot'buildingout sections 'for balancing said lines, switching means forconnecting said basic network in circuit with a line to be balanced, andswitching means tor subsequently balancing another et said lines byconnecting` in circuit therewith said basic network and one of saidbuilding-out sections.

32. In a signaling system, a plurality of real lines to be balanced,said lines having fwidely different iinpedances, a common basic networkfor said lines, and switching means for connecting said basic network attimes to one or said lines and at otheir times to another of ,id lineswhile maintaining the same degree of balance for bot-h of said lines,

The combination of sion line, a repeater an therefor, said artificialline bavii an imM pedance less than` the impedanceloit said transmissionl ine and nica-ns responsive to the association ot said. repeater withsaid transmision line to change said artificial line to a valuesimulating the impedance ot said transmission line` 34. In a signalingsystem, a plurality of lines, repeaters for interconnecting said lines,balancing networks for said lines, a master relay individual to eachrepeater, means un- CIT der the control. of Suid master relay forSelecting n balancing network for one of said linee, means for selectinga balancing' network for L second of said lines wherebyntercoininnnieation iS establisheci between said lust two lines, andmeans responsive to snici first selection for transferring the conifi-eiof Suid muster relay te said Second means whereby the second balancingnetwork is selected.

In witness whereoiI hereunto subscribe my nume this 23rd dey ofDecember, A. D.

ROY D. CONVVLv Y.

